Army Secretary John McHugh has stripped Brig. Gen. Jeffrey Sinclair of two grades, forcing him to retire from service as a lieutenant colonel.

This is the first time the Army has reduced a retiring general officer by two ranks in a decade, according to the service’s announcement Friday.

Sinclair, who in March pleaded guilty to having a three-year affair with a female subordinate, has already received a judge’s reprimand and a $20,000 fine.

Sinclair’s case unfolded in a Fort Bragg, N.C., military court as Congress debated whether to remove commanders from decision-making authority over military sexual assault within their chain of command.

The 51-year-old general had been accused of twice forcing the female captain to perform oral sex during the three-year affair, but the sexual assault charges were dropped as part of the plea deal. The prosecution for sexual assault crumbled after questions arose about his primary accuser’s credibility and whether military officials improperly rejected a previous plea deal because of political concerns.

McHugh said he is prevented by federal law from taking further action, and did what he called, “legally sustainable.”

“During Capitol Hill hearings, I was asked whether Sinclair would receive a pension after proceedings were complete,” McHugh said. “Under federal law, if a person has earned a pension because of their years of service, they are entitled to those benefits; Congress might consider a change in the law that would allow greater flexibility and accountability.”

Sinclair’s guilty plea included adultery, maltreatment of a subordinate, engaging in improper relationships, willful disobedience of an order, wrongful use of a government travel card, wrongful possession of pornography, and conduct unbecoming an officer. The judge could have sentenced him to a maximum of more than 20 years in prison and dismissal from the Army.

“While retirement benefits are mandated by federal law, there is a requirement that an individual must have served satisfactorily in rank before receiving those benefits,” McHugh said in a statement. “Sinclair displayed a pattern of inappropriate and at times illegal behavior both while serving as a brigadier general and a colonel. I therefore decided there was sufficient evidence and cause to deny him those benefits.”

Sinclair’s attorney Richard Scheff, in response to the Army’s announcement today, said the general had “consistently taken responsibility for his mistakes and agreed to a reduction in retirement benefits.” He also noted that until Sinclair’s reduction in retirement grade takes effect when he leaves active duty in several weeks, he remains an Army brigadier general.

“He is a highly decorated war hero who made great sacrifices for his country, and it’s right that he be permitted to retire honorably,” Scheff said.